A conventionally known gas sensor is configured such that a gas detection element (microsensor chip) is mounted on a package (wiring substrate) on which terminals for input from and output to an external circuit are formed and such that a cover in which a plurality of gas inlets are formed for introducing therethrough a gas to be measured is fixedly attached to a perimetric frame of the package (refer to, for example, Patent Document 1). Another conventionally known gas sensor is configured such that a gas detection element is held via a lead frame in a suspended condition by a quadrangular, tubular fixation element and such that the fixation element is fixedly covered at its top face with a cover element in which a plurality of gas inlets are formed for introducing therethrough a gas to be measured, and at its bottom face with a shield cover element (refer to, for example, Patent Document 2).    Patent Document 1: Japanese Patent Application Laid-Open (kokai) No. H11-233240    Patent Document 2: Japanese Patent Application Laid-Open (kokai) No. H09-21774